Magnesium alloy



' 2 or calcium.

Patented Aug. 9, 1938 um'rso STATE 5 PATENT orrics- MAGNESIUM QALLOY John Leslie Haughton and William Eliezer Prytherch, Teddington, England No Drawing.

Application September 22, 1936,

Serial No. 102,048. In Great Britain October '1,

in magnesium.

The invention is based upon the observation I that by the inclusion in magnesium alloys rich in. 5 magnesium of both aluminum and silver in proportions within the limits stated below in the presence or absence of certain other elements, as

for instance one or more of the following, namely,

manganese, zinc or calcium products which retain or develop stress resisting properties at temperatures above atmospheric temperature may be obtained.

The invention consists, broadly, therefore, in

magnesium alloys and particularly magnesium alloys rich -in inagnesium containing from 6 to 8 per cent. of aluminium and 1.5.to 3 per cent.

of silver, the balance consisting of magnesium in an amount not less than '79 per cent. of the alloy.

The invention further extends to magnesium alloys containing the pair of metals aluminium and silver and magnesium inproportions between the limits stated, in association with a proportion of one or more oi the elements, manganese, zinc Normally the proportion of manganese alone may be up to about 4 per cent. and the proportion of zinc or calcium alone may be up to about 6 percent. of each of these elements. The following particulars are given to iilustrate the composition of certain alloys withv in the scope of the invention and the properties thereof:

. Magnesium rich alloys containing aluminium between 6 per cent. and 8 per cent. and silver between 1.5 per cent. and 2.5 per cent., the balance being magnesium, resist stress up to temperatures up to at least 100 0., thus for instance an alloy having the following. nominal composition, 40 namely, aluminium 7.5 per cent., silver 2 per cent., the balance being magnesium, gave the. following results when subjected to tensile stress: 1

Temperatures Tons/sq. in.

The above detailed particulars refer to ternary alloys which in addition to the essential pair of elements aluminium' and silver contain only magnesium.

For purposes of comparison it may be mentioned that a magnesium alloy containing hum-'- inaliy 7 per cent. of aluminium and 2 per cent. of

silver had an ultimate tensile strength of 19.9 tons per square inch at room temperature:

In order to develop the best properties in alloys containing the pair of metals, aluminium and silver together with certain other elements as above referred to, they may with advantage be s'ubjectedto a heat treatment, consisting of heating the alloy'to about400 C. for 15 minutes or more and then hardening by heating at a lower temperature, say to 220 C. for one or more days.

The production of alloys including the pair of metals aluminium and silver is conveniently eifected by melting magnesium or a magnesium rich alloy under a suitable flux and then adding the aluminium and silver in suitable quantities 3 and in the case where more complex alloys are to be produced by adding aluminium and silver together with manganese, calcium or zinc either as metals or as magnesium rich alloys to the molten magnesium.

We claim: I

A magnesium alloy containing a proportion of aluminium within the limits 6 and 8 per cent., a proportion of silver within the limits 1.5 and 3 per cent., the balance being magnesium.

JOHN HAUGHTON.

WILLIAM ELIEZER PRYTHERCH. 

